Question

TIME AL a. Make a neat labeled sketch of a hydraulic power unit. (5mks) b. State 5 most common problems found in a ship's hydraulic operated remote valve Q1. system. (5mks) c. Troubleshoot the above(b) (10mks) Q2. a. What are hydraulic strainers?(5mks) b. Illustrate how strainers are positioned in hydraulic reservoirs.(7mks) Neatly sketch and explain the function of a single acting spring type hydraulic cylinder.(8mks) Q3. C. a. Fluid contamination can be as a result of the ff. factors; a. system design inadequacy; b. poor maintenance of the system; c. poor housekeeping of the system; operating conditions. Carefully elaborate on each of these factors and how they affect the system operation.(10mks) b. What are the causes of aeration and their effect on a hydraulic system?(3mks) c. List 7 points to observe in order to ensure proper fluid contamination control.(7 mks) adverse Q4. a. Write all you know about hydraulic fluid sampling. (5mks) b. Explain with sketches how a windlass hydraulic motor could be reversed.(10mks) c. What is the purpose of the hydraulic accumulator?(5mks) Q5. a. List 7 advantages of fluid power. (10mks) b. Why would you choose fluid power system over mechanical system.(5mks) c. State 2 hazards associated with pressurized hydraulic fluid. (5mks) Q6. a. Indicate 5 areas in the offshore and shipping industries where hydraulics power is dependent.(5mks) b. What are the factors to be considered before trouble shooting a hydraulic unit.(7mks) c. Give the 5 organized problem solving efforts in hydraulics.(8mks) jft Last Update: 15/04/08 Approved: DAA Issue No.: 1 1/1 Doc. No.: EXM/F/03 Revision No.: 1 Page No.: Date: 12/04/06 Author: EC

Answer 1

Q 2 } A

Hydraulic Strainers :

A strainer is a tool made of wire mesh screens used to remove large solid particles from a fluid . strainers are installed on pipelines ahead of valves, pumps and regulators to protect them from the damaging effects of fluid and other system contaminants. A common strainer design uses two screens, cylindrical in shape. One cylinder is inside the other and the two are separated by a small space.

Q 5 } A

Advantage of fluid power :

>  The main advantage of a fluid power system is how the power is transmitted. In the fluid power system, we can use a single Pump to power many hydraulic cylinders with the help of pressure valves.

> Control of wide range of speed and forces is easily possible.

> High efficiency with low friction loss keeps the cost of a power transmission low .

> Fluid power systems can provide widely variable motions in both rotary and straight-line transmission of power.

> fluid   power systems are economical to operate.

> motion can be almost instantly reversed

>  Automatic valves protect the system against a breakdown from overloading.